Calibrated pressure regulator

ABSTRACT

A miniaturized pressure regulator capable of being calibrated and thus making it possible to dispense with an additional pressure gauge, if desired. The components of the pressure regulator are maintained in position by leaf spring fasteners making it possible to quickly assemble and disassemble the pressure regulator.

United States Patent Baranowski, Jr.

CALIBRATED PRESSURE REGULATOR Oct. 24, 1972 1 3,516,442 6/1970 Munroe..251/367 X 3,134,405 5/1964 White ..251/297 X 72] Inventor. FrankBaranowski Jr. 7 Pine Street, Lynnfield Mass. 3,286,726 11/1966 Guy..l37/505.42 X 01940 2,918,081 12/1959 Laver ..137/505.42 X

[22] Filed; 11, 1970 FOREIGN PATENTS OR APPLICATIONS 2 APPL 97 1071,058,401 11/1953 '7 France, ..137/505.42

' i I I Primary Examinere-Harold W. Weakley [52] US. Cl. ..137/327,137/315, 137/505.42, A t j E. Mrose 251/297, 251/367 v [51 Int. Cl..Fl6k 31/365 [57] ABSTRACT [58] Field of Search ..137/505.41, 505.42,505.11, 7 A d p g t p bl f b 1 Ze reSSure re a0! Ca 3 e O 6mg calibratedand thus making it possible to dispense with [56] References Cited anadditional pressure gauge, if desired. The components of the pressureregulator are maintained in UNITED STATES ATEN position by leaf springfasteners making it possible to quickly assemble and disassemble thepressure regula- 2,819,728 1/1958 Gage ..137/505.11 X ton 1,244,22610/1917 Metzger ..137/505.37 X

763,162 6/1904 Curran ..137/505.42 6 Claims, 6 Drawing Figures 7e 8, 198 9d J\% ,ea T

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a l y wmrw CALIBRATED PRESSURE REGULATOR BACKGROUND OF INVENTION SUMMARYOF INVENTION ,A pressure regulator embodying this invention includes aregulator body defining an inlet passageway, an outlet passageway and avalve seat passageway interconnecting said inlet passageway and saidoutlet passageway. A movable valve element cooperates with the valveseat formed by said valve seat passageway. Said valve element is biasedby a spring to the closed position thereof. A diaphragm operating saidvalve element is arranged to be acted upon on the side thereof adjacentsaid valve element by fluid pressure prevailing downstream of said valveelement. A calibrating spring engages, and rests with one end thereofagainst, the side of said diaphragm remote from said valve element. Amanually operable screw-threaded pressure control member is arranged incoaxial relation to said valve element and has an abutment surfaceengaged by the other end of said calibrating spring. A pressureregulator embodying this invention further includes a calibrating memberhaving a screw thread cooperating with the screw thread on said pressurecontrol member and pivotable about the joint axis of the screw thread ofsaid pressure control member and said screw thread of said calibratingmember. This makes it possible to vary the compression of saidcalibrating spring without pivotal motion of said pressure controlmember relative to said regulator body.

BRIEF DESCRIPTION OF DRAWINGS DESCRIPTION OF PREFERRED EMBODIMENT ln thsdrawings reference numeral 1 has been applied to indicate a regulatorbody defining a screw-threaded inlet passageway la, a screw-threadedoutlet passageway lb and a valve seat passageway 1c interconnecting theinlet passageway la with the outlet passageway 1b. Passageway forms thevalve seat 2. Movable valve element 3 cooperates with valve seat 2 andis biased to the closed position thereof by the helicalvalve-element-biasing spring 4. The upper portion of regulator body 1has a recess forming a diaphragm chamber 5b receiving a diaphragmgenerally indicated by numeral 5. The latter includes a circular disc 5cof an elastomer, e.g., rubber, which engages a conforming circular rimof the regulator body 1 and a pair of circular metal discs 5asandwichung the center portion of disc 50. Diaphragm 5 is subjected atthe lower surface thereof, i.e., the side thereof adjacent valve element3,

to the pressure of fluid prevailing at the region downstream of valveelement 3. The lower end of helical calibrating spring6 engages, andrests against, the

upper surface of diaphragm 5, or the side thereof remote from valveelement-3. The upper end of spring 6 engages and abuts against themanually operable pressure control member, or pressure control knob 7.

The outer surface of regulator body 1 is substantially in the shape of asolid of revolution, and valve element 2, helical springs 4and 6,diaphragm 5 and pressure control knob 7 are arranged in coaxial relationto the outer surface of regulator body 1. Pressure control knob 7 isprovided with a coaxial cavity 7a which is internally screw-threaded asindicated at 7b. The top of cavity 7a forms an abutment 7d engaginghelical calibrating spring 6. Pressure control knob 7 is furtherprovided with an axial eccentric bore 70, i.e., a bore extendingparallel to the axis of pressure control knob 7, but in radially spacedrelation from the axis of pressure control knob 7. Reference numeral 8has been applied to indicate a tubular calibrating member having anexternal screw thread 8a cooperating with, or engaging, the

internal screw thread 7b of pressure control knob 7. Calibrating member8'is pivotable both in clockwise and in counterclockwise direction aboutthe joint axis of screw threads 7b and 8a to vary the compression ofcalibrating spring 6 without pivotal motion of pressure control knob 7relative to regulator body 1. How such a pivotal motion of calibratingmember 8 relative to regulator body 1 can best be achieved will be setforth below more in detail.

The calibrating member 8 includes a lower outwardly flaring flangeportion 8b which has a larger diameter than the diameter of thescrew-threaded portion of calibrating member 8. The large diameter ofthat flange portion is substantially equal to the diameter of thediaphragm 5, and the latter is sandwiched between the upper rim ofregulator body 1 and the flange portion 8b of calibrating member 8. Thecylindrical screw-threaded small diameter portion of the calibratingmember 8 is provided with one or more tool-receiving recesses orradially extending bores 80. By insertion of an appropriate tool intorecesses or bores the calibrating member 8 may be pivoted about'thejoint axis of the same and of parts 1,3,4,5,6 and 7 without effecting apivotal motion of pressure control knob 7 relative to regulator body 1.A pivotal motion of calibrating member 8 without concomitant pivotalmotion of pressure control knob 7 results in raising, or lowering of thelatter, as the case may be, and in allowing calibrating spring 6 toexpand, or in a compression of the latter.

Reference character 9 has been applied to indicate a substantiallyannular clamping member having a circular aperture 9a and asubstantially circular abutment aperture 9a. The screw-threaded portionof relatively small diameter of calibrating member 8 projects throughaperture 9a. The abutment surface 9b of clamping member 9 engages therelatively large diameter flange portion 8b of calibrating member 8 andclamps portion 8b of calibrating member 8 against diaphragm 5 andregulator body 1.

The structure further includes a plurality preferably three generallyC-shaped clamping leaf springs (FIGS. 2,3 and 5) angularly displaced inre gard to the joint axis of parts 1,2,3,4,5,6,7 and 8. Each leaf spring10 engages with one end thereof one of a plurality of spring-receivingrecesses 90 in clamping member 9. The axial bore 7c in pressure controlknob 7 is provided with an index pin 11 biased in axial direction by apin-biasing helical spring 12. Clamping member 9 has an upstandingridge-like projection 9d for engaging pin 1 1 and thereby defining limitpositions for pressure control knob 7. In other words, the upstandingridge-like projection 9d of clamping member 9 and the pin 11 jointlymovable with pressure control knob 7 are cooperatinglimit-position-establishing abutment means. One of these limit positionswould normally mean that the passage defined by valve element 3 andvalve seat 2 is open to such an extent that a predetermined constantpressure prevails in the outlet passageway b of valve body 1. In theother of these limit positions calibrating spring 6 is compressed tosuch an extent as to preclude passageof any fluid from inlet passageway1a to outlet passageway 1b.

Each clamping leaf spring 10 has a substantially S- shaped end 10aengaging a cooperating clamping cam surface 9f and a recess 9c inclamping member 9. The other end 10b of each leaf spring 10 issubstantially hook-shaped, or U-shaped, and engages a substantiallyconforming spring-end-receiving recess 1d of regulator body 1 which isclosed by a ridge 1e. The hook-shaped, or U-shaped ends 10b of clampingspring 10yare relatively stiff, or have a relatively small mechanicalcompliance, while the S-shaped ends 10a of clamping springs 10 arerelatively flexible, or have a relatively large mechanical compliance.The ridges 1e in regulator body 1 closing recesses 1d have a radius ofcurvature which is, at least in part, equal to the radius of curvatureof the hook-shaped, or U-shaped ends 10b of leaf springs 10. Clampingmember 9 is also a cover means. Its spring-receiving recesses 90 areeach closed by a ridge 9f having a smaller radius of curvature than theradius curvature of the bend of the S-shaped end 10 a of each spring 10remote from valve body 1. This configuration of springs 10 and of theportions of parts 1 and 9 engaged by springs 10 makes it possible tocombine a firm clamping action by springs 10 on parts 1 and 9, resultingin stressing of springs 10 in a direction longitudinally thereof, withthe possibility of ready assembly and disassembly of the pressureregulator due to the large mechanical compliance of the S-shaped ends10a of springs 10 and the cam action of the ridges 9f closing recesses90 tending to expand springs 10 when the latter are inserted into, orremoved from, parts 1 and 9.

The lower end surface 7e of pressure control knob 7,

- i.e., the end surface of knob 7 adjacent regulator body 1, has adiameter considerably larger than the major diameter of screw-thread 7b,and the major diameter of screw-thread 8a. The diameter of end surface7e of knob 7 is substantially equal to, or but slightly smaller than,the diameters of regulator body and clamping member 9 at the sidethereof adjacent control knob 7 whereby a region of limitedaccessibility if established adjacent the end surface 7e of knob 7. Thetool-receiving recesses 8c in calibrating member 8 are situated in theaforementioned region of limited accessibility. This is desired in orderto preclude accidental changes in the calibration of the regulator whichwould be caused by an unintentional pivotal motion of calibrating member8 relative to regulator body 1. The fact that tool-receiving recesses 80are not exposed to view from the front of the regulator, and arearranged in a region of limited accessibility, tends to precludetampering with the calibration of the regulator by incompetentpersonnel.

Only one who knows the hidden place of calibration control, and has theright tool fitting into recesses 80 will be in a position to change thecalibration of the pressure regulator whenever necessary, or desirable.In many instances a regulator once having been calibrated to maintain acertain pressure at the outlet passageway 1b thereof does not need to berecalibrated.

Clamping member 9 is provided on the end surface thereof adjacentpressure control knob 7 with a plurality of indexing recesses 9e (FIG.3) arranged in a circular pattern conforming with the circulartrajectory of index pin 11 resulting from pivotal motions of knob 7about the axis thereof. Index pin 11 is provided on the end thereofwhich projects axially outwardly beyond end surface of knob 7 with asubstantially hemispherical tip which engages the indexing recesses 9ein clamping member 9 when knob 7 is pivoted relative to clamping member9 and regulator body 1.

As clearly shown in FIG. 1 the valve-element-biasing spring 4 has anupper end engaging valve element 3 and I a lower end engaging awasherlike abutment member 13 provided with apertures for the passage ofgas under pressure from a tank filled with gas under pressure to valveseat passageway 10. The inlet passageway 1a is provided with an insert14 screwed into valve body 1 and forming a valve chamber 14a. The latterhouses a filter 15 and an O-ring' 16 is interposed between filter 15 andabutment member 13.

In the structure of FIG. 1 the the insert 14 of inlet passageway 1a anddischarged through outlet passageway 1b has substantially a right angleflow pattern as indicated by two arrows of which one indicates thedirection of flow of fluid into the pressure regulator, and the otherindicates the direction of the flow of fluid out of the pressureregulator. It is apparent from FIG. 1 that the direction of the flowinto the pressure regulator is substantially axial and the direction offlow out of the pressure regulator is substantially radial. In someinstances it is desirable to admit fluid to the pressure regulator in aradial direction and to withdraw fluid from the pressure re gulator alsoin radial direction. For this reason it is desirable to design apressure regulator in such a way that it can readily be modified toallow admission of gas to it in a radial direction. How this can beachieved will be shown below more in detail.

The structure as described above is capable of being calibrated, i.e.,adjusted in such a way that each position of knob 7 corresponds to apredetermined pressure so as to dispense with a pressure gauge. In someingas admitted throughstances it is, however, desirable to provide thepressure regulator with a pressure gauge in order to make it possible tocheck its calibration from time to time. How this can be achieved willlikewise be set forth below more in detail. a

As shown in FIG. 2 regulator body 1 defines, in addition to the outletpassageway 1b, a pair of internally screw-threaded recesses la. One ofthese recesses 1a is also shown in FIG. 1. The median planes of outletpassageway lb and of recesses 1a enclose angles of 120. Normallyrecesses 1a do not communicate with diaphragm chamberSb. The upper wallof one or both recesses la may be pierced so that the particular recess1a then communicates with diaphragm chamber 5b. Assuming that but one ofscrew-threaded recesses 1a communicates with diaphragm chamber 5b, thenthe same pressure prevails in that recess la as in the outlet passagewaylb. Hence a pressure gauge screwed into the particular recesscommunicating with diaphragm chamber 5b will indicate the pressureprevailing in diaphragm chamber 5 and may be used to calibrate thepressure regulator, and to check from time to time the calibrationthereof.

If it is desired to admit gas radially rather than axially to thepressure regulator, insert 14 which defines an axial passage is replacedby an insert which defines a radial passage. This radial passage isextended into one of the screw-threaded recesses 1a by providing anaperture in the partition 1f of regulator body 1. If this change iseffected the radial recess 1a becomes the inlet passageway of thepressure regulator. The internal screw-thread lg in the base portion ofthe regulator body 1 which is normally used to secure the pressureregulator to a gas tank may then be used to affix the pressure regulatorto any support having a matching external screw-thread. The internalscrew-thread in recess la turned into an inlet passageway is then usedto connect the pressure regulator to a supply of gas under pressure.When the pressure regulator is modified as indicated above a filter maybe interposed between the recess la which forms the inlet passageway andthe valve chamber 14a.

If it is intended to use any one of the two recesses 1a for connecting apressure gauge to the pressure regulator, the partition 1g is pierced,so as to connect the diaphragm chamber 5b with the particularscrewthreaded recess 1a to which it is intended to connect a pressuregauge.

The valve element 3 includes a portion which is substantially in theshape of a frustum of a cone and engages the valve seat 2, and a portionwhich is cylindrical and forms a shoulder against which the upper end ofthe biasing spring'4 of the valve element 3 rests. The valve stem 4aprojects through valve element 3, and its upper end engages a bossintegral with diaphragm 5. Valve element 3 is firmly affixed to valvestem 4a. The former is preferably of polytetrafluoroethylene for reasonsmore fully set forth in my copending patent application Ser. No. 97,276,filed Dec. 11, 1970 for FLUID FLOW CONTROL VALVE to which reference maybe had for a preferred way of formingparts 3 and 4a.

Most parts of which the pressure regulator is made lend themselves todie casting. The pressure control member or knob 7 is preferably a diecasting provided with six pocket-like recesses 7f to limit the mass andweight thereof (FIG. 4). Recesses 7f have open ends arranged in theplane defined by the end surface 7e of knob 7, and their opposite endsare closed. As clearly shown in FIG. 2 the sides of knob 7 are fluted tofacilitate its manipulation.

' Referring to FIG. 3, when index pin 11 abuts against the lower surfaceof abutment ridge 9d of clamping member 9 the valve 2,3 is fully closedby the action of helical biasing spring 4. Accordingly, this position ofknob '7 is marked on the upper surface of clamping member 9 by an OFFsign. On the other hand, if knob 7 is rotated counterclockwise about 360from the position shown in FIG; 3 until its index pin 11 abuts againstthe upper surface of abutment ridge 9d of clamping member 9, the valve2,3 is as fully open as possible. Accordingly this position of knob 7 ismarked on the upper surface of clamping member 9 by an ON sign. In thisposition the difference in fluid pressure prevailing in valve chamber14a, on the one hand, and in outlet passageway 1b, on the other hand, isminimized. If it is desired to maintain a predetermined constantpressure in outlet passageway lb the regulator may be adjusted in such away that this pressure is maintained as long as index pin 11 abutsagainst the upper surface of abutment ridge 9d. Any other position ofpin 11 and of knob 7 then results in a smaller pressure inside of outletpassageway 1b than the aforementioned predetermined constant pressure,and if knob 7 is rotated in clockwise direction (FIG. 3) until its pin11 abuts against the lower surface of abutment ridge 9d, the pressure inoutlet passageway lb is zero. There is a one to one correspondencebetween each position of parts 7 and 11, andthe pressure prevailing inoutlet passageway 1b.

When it is intended to calibrate the pressure regulator, the intakepassageway 1a and the valve chamber 14a are connected to a source of gasunder pressure, e.g., a tank filled with propane gas, and the pressureprevailing downstream of the valve seat 2, e.g., in passageway 1b, ismeasured by means of a conventional pressure gauge. Prior to thisoperation the pressure control knob 7 has been turned to the fully openposition, i.e., the position when one side of the index pin 1 l abutsagainst one side of the upstanding ridge 9d of clamping member 9. Now anappropriate tool (not shown) is inserted in one of the tool-receivingrecesses of calibrating member 8, and the latter is pivoted about itsown axis until the pressure gauge indicates the pressure intended to beassociated with the fully open position of the regulator. Assuming thatthe pressure regulator .is intended to be used for reducing the pressureof a gas stored in a tank at a relatively high pressure to 25 lbs/inf,which pressure is to be maintained constant, e.g., for the purpose ofoperating a torch, or a spray gun. Under such conditions the calibratingmember 8 is adjusted or pivoted about its axis in such a way that thepressure gauge indicates the desired pressure at the outlet passageway1b. Then the predetermined constant pressure of 2S lbs/in. will alwaysbe established at the outlet passageway 1b by merely turning knob 7 toitsinitial calibrating position in which pin 7 engagesthe upper surfaceof ridge 9d (FIG. 3).

Assuming that the index or detent pin 11 of knob 7 .is in engagementwith one of the recesses 9e of clamping member 9 when the regulator iscalibrated, as stated above, by means of a pressure gauge andbyadjusting calibrating member 8. Then turning knob 7 to the very sameposition results always in the very same pressure in outlet passageway1b. If knob 7 is not quite turned to that position, the pressure inpassageway 1b will be less than, and if knob 7 is turned beyond thatposition, the pressure in passageway 1b will exceed, the pressureprevailing in passageway lb with index or detent pin 11 in theaforementioned position. Since there is a one to one relation betweenthe positions of pin 11 and the pressure prevailing in passageway 1b theupper surface of clamping member 9 may be calibrated in terms of variouspressures prevailing in outlet passageway lb, and since it is possibleby adjusting calibrating member 8 to establish a. desired pressure inoutlet passageway 1b with knob 7 and pin 11 in any desired position, theupper surface of clamping member 9 may be provided with a scale forreading off pressures prevailing in outlet passageway lb. This makes itpossible to dispense with a pressure gauge though the proper adjustmentof calibrating member 8 should be checked from time to time by means ofa pressure gauge. The use of such gauge may, however, be limited tomaintenance operations, i.e., called for in relatively long intervals oftime.

Referring now to FIG. 6, reference character R has been applied thereinto indicate a pressure regulator of the same character as shown in FIGS.1 to 5, inclusive, and described in the context thereof. The pressureregulator R is mounted on top of a tank or bottle B filled with acombustible gas under pressure, e.g., propane. The blow torch T ispivotally connected to the outlet passageway of pressure regulator R,its axial inlet passageway being supplied with gas under pressure fromtank or bottle B. Air for combustion is added to the fuel at the pointor nozzle N, and the flame tube T is provided with an internal system ofhelical vanes (not shown) for establishing a thorough mixture of fueland air inside of flame tube T. Blow torches of this description requirefor best performance maintenance of a critically constant gas pressurewhich is assured by the provision of the compact pressure regulator R onthe top of tank or bottle B.

In the structure of FIG. 6 the position of the flame tube T and of theflame which issues from the latter are not dependent upon the positionof the bottle or tank 3. Hence the flame can more readily be establishedwherever needed, particularly in close quarters where there is no accessfor the tank or bottle B. Assuming that it is desired to use a flametube of the torch in a horizontal position to obtain a horizontal flamein relatively close quarters, this may be achieved either with the tankor bottle B in an erected position as shown in FIG. 5, or in a bottom upor inverted position with the pressure regulator R at a lower level thanthe tank or bottle B proper.

I claim as my invention:

1. A pressure regulator including a. a regulator body having an outersurface substantially in the shape of a solid of revolution, saidregulator body defining an inlet passageway, an outlet passageway and avalve-seat-forming passageway interconnecting said inlet passageway andsaid outlet passageway;

b. a movable valve element cooperating with the valve seat formed bysaid vaive-seat-forming passageway to vary the eflective area of saidvalveseat-forming passageway;

c. a first spring means biasing said valve element to the closedposition thereof;

d. a second spring means biasing said valve element to the open positionthereof;

e. a diaphragm interposed between said valve element and said secondspring means and arranged to be acted upon by fluid pressure prevailingdownstream from the location of said valve-seat;

f. a pressure control knob arranged in coaxial rela tion to saidregulator body, provided with a screwthread and forming an abutment forthe end of said second spring remote from said diaphragm;

g. a calibrating member arranged in coaxial relation to said regulatorbody, supported by said regulator body, pivotable about the axis of saidregulator body relative to said regulator body and having a screwthreadin cooperative engagement with said screw-thread on said pressurecontrol knob, the pivotal motion of said calibrating member about theaxis of said regulator body relative to said re gulator body resultingin a change of the axial spacing of said pressure control knob from saidregulator body without pivotal motion of said pressure control knobrelative to said regulator body; and

h. said knob having an end surface adjacent said regulator body which isof diameter considerably larger than the major diameter of saidscrewthread of said pressure control knob and the major diameter of thescrew-thread of said calibrating member and substantially equal to thediameter of the portion of said regulator body adjacent said controlknob, whereby a region of limited accessibility is established adjacentsaid end surface of said control knob; and wherein i. the radially outersurface of said calibrating member is provided with a tool-receivingrecess located in said region of limited accessibility.

2. A pressure regulator as specified in claim 1 wherein a. saidcalibrating member is provided with an out- .wardly flaring portionengaging the outer periphery of said diaphragm;

. an annular clamping member is arranged between said pressure controlknob and said outwardly flaring portion of said calibrating member, saidcalibrating member extending axially through said annular clampingmember and the outer periphery of said clamping member engaging theouter periphery of said outwardly flaring portion of said calibratingmember; and wherein c. a plurality of leaf clamping springs engagingsaid regulator body and said clamping member with opposite ends thereofclamp said clamping member and said outwardly flaring portion of saidcalibrating member against the outer periphery of said diaphragm andagainst said valve body.

3. A pressure regulator as specified in claim 2 wherein a. said pressurecontrol knob is provided with a bore extending parallel to the axisthereof and receiving a spring-biased index pin projecting beyond theend surface of said pressure control knob adjacent said regulator bodyand having a substantially b. the surface of said annular clampingmember adjacent said end surface of said pressure control knob isprovided with a plurality of indexing recesses arranged in a circularpattern conforming with the circular trajectory of said hemisphericaltive area of said valve-seat-fomiing passageway; cover means arranged incoaxial relation to said valve body to close an opening in said valvebody, said cover means having on the outer surface thereof threerecesses angularly displaced 120 and each arranged in a common planewith the axis of said. valve body and one of said three recesses on saidouter surface of said valve body;

d. three generally C-shaped clamping leaf springs each engaging with oneend thereof on of said three recesses in said outer surface of saidvalve body and each engaging with the other end thereof tip of saidindex pin resulting frompivotal motions of said pressure control knobabout said axis 10 thereof.

4. A pressure regulator as specified in claim 3 wherein said surface ofsaid annular clamping member One Of Said three recesses in Said Covermeans; and is provided with an upstanding projection forming a whereinpair of abutment surfaces for said index pin and limiteach of Said threeamping eaf prings has a Subing the freedom of pivotal motion of saidpressure con- Stantia-uy P end and a Substantially hooktrol knob aboutsaid axis thereof. h p and wherein 5, A pressure lat as ifi d i l i 2 f.said three recesses in said outer surface of said wherein each of saidplurality of clamping springs has a Valve y and Said three recesses inSaid Cover substantially S-shaped end and a substantially hookmeansare'shaped such fashion h h of shaped nd, said recesses receiving saldsubstantlally hook- 6, A val e structure in l di shaped end of one ofsaid clamping leaf springs is a. a valve body having an outer surfacesubstantially closed y ridge having at F in P a radius of in the shapeof a solid of revolution and defining an curvature equal to the radlusof Curvature of the inlet passageway, an outlet passageway and avalve-seat-forming passageway connecting said inlet passageway to saidoutlet passageway, said hook-shaped end of each of said clamping leafsprings, and that each of the recesses receiving said substantiallyS-shaped end of one of said clamping leaf springs is closed by a ridgehaving a smaller radius of curvature than the radius of curb. a movablevalve element inside said valve body vature P the bend of said s'shapedand remote cooperating with the valve seat formed by said from saldvalve bodyvalve-seat-forming passageway to vary the effecvalve bodyhaving on said outer surface thereof three recesses angularly displaced120;

1. A pressure regulator including a. a regulator body having an outersurface substantially in the shape of a solid of revolution, saidregulator body defining an inlet passageway, an outlet passageway and avalve-seat-forming passageway interconnecting said inlet passageway andsaid outlet passageway; b. a movable valve element cooperating with thevalve seat formed by said valve-seat-forming passageway to vary theeffective area of said valve-seat-forming passageway; c. a first springmeans biasing said valve element to the closed position thereof; d. asecond spring means biasing said valve element to the open positionthereof; e. a diaphragm interposed between said valve element and saidsecond spring means and arranged to be acted upon by fluid pressureprevailing downstream from the location of said valveseat; f. a pressurecontrol knob arranged in coaxial relation to said regulator body,provided with a screw-thread and forming an abutment for the end of saidsecond spring remote from said diaphragm; g. a calibrating memberarranged in coaxial relation to said regulator body, supported by saidregulator body, pivotable about the axis of said regulator body relativeto said regulator body and having a screw-thread in cooperativeengagement with said screw-thread on said pressure control knob, thepivotal motion of said calibrating member about the axis of saidregulator body relative to said regulator body resulting in a change ofthe axial spacing of said pressure control knob from said regulator bodywithout pivotal motion of said pressure control knob relative to saidregulator body; and h. said knob having an end surface adjacent saidregulator body which is of diameter considerably larger than the majordiameter of said screw-thread of said pressure control knob and themajor diameter of the screw-thread of said calibrating member andsubstantially equal to the diameter of the portion of said regulatorbody adjacent said control knob, whereby a region of limitedaccessibility is established adjacent said end surface of said controlknob; and wherein i. the radially outer surface of said calibratingmember is provided with a tool-receiving recess located in said regionof limited accessibility.
 2. A pressure regulator as specified in claim1 wherein a. said calibrating member is provided with an outwardlyflaring portion engaging the outer periphery of said diaphragm; b. anannular clamping member is arranged between said pressure control knoband said outwardly flaring portion of said calibrating member, saidcalibrating member extending axially through said annular clampingmember and the outer periphery of said clamping member engaging theouter periphery of said outwardly flaring portion of said calibratingmember; and wherein c. a plurality of leaf clamping springs engagingsaid regulator body and said clamping member with opposite ends thereofclamp said Clamping member and said outwardly flaring portion of saidcalibrating member against the outer periphery of said diaphragm andagainst said valve body.
 3. A pressure regulator as specified in claim 2wherein a. said pressure control knob is provided with a bore extendingparallel to the axis thereof and receiving a spring-biased index pinprojecting beyond the end surface of said pressure control knob adjacentsaid regulator body and having a substantially hemispherical tip on theend thereof projecting beyond said end surface of said pressure controlknob; and wherein b. the surface of said annular clamping memberadjacent said end surface of said pressure control knob is provided witha plurality of indexing recesses arranged in a circular patternconforming with the circular trajectory of said hemispherical tip ofsaid index pin resulting from pivotal motions of said pressure controlknob about said axis thereof.
 4. A pressure regulator as specified inclaim 3 wherein said surface of said annular clamping member is providedwith an upstanding projection forming a pair of abutment surfaces forsaid index pin and limiting the freedom of pivotal motion of saidpressure control knob about said axis thereof.
 5. A pressure regulatoras specified in claim 2 wherein each of said plurality of clampingsprings has a substantially S-shaped end and a substantially hook-shapedend.
 6. A valve structure including a. a valve body having an outersurface substantially in the shape of a solid of revolution and definingan inlet passageway, an outlet passageway and a valve-seat-formingpassageway connecting said inlet passageway to said outlet passageway,said valve body having on said outer surface thereof three recessesangularly displaced 120*; b. a movable valve element inside said valvebody cooperating with the valve seat formed by said valve-seat-formingpassageway to vary the effective area of said valve-seat-formingpassageway; c. cover means arranged in coaxial relation to said valvebody to close an opening in said valve body, said cover means having onthe outer surface thereof three recesses angularly displaced 120* andeach arranged in a common plane with the axis of said valve body and oneof said three recesses on said outer surface of said valve body; d.three generally C-shaped clamping leaf springs each engaging with oneend thereof on of said three recesses in said outer surface of saidvalve body and each engaging with the other end thereof one of saidthree recesses in said cover means; and wherein e. each of said threeclamping leaf springs has a substantially S-shaped end and asubstantially hook-shaped end; and wherein f. said three recesses insaid outer surface of said valve body and said three recesses in saidcover means are shaped in such a fashion that each of said recessesreceiving said substantially hook-shaped end of one of said clampingleaf springs is closed by ridge having at least in part a radius ofcurvature equal to the radius of curvature of the hook-shaped end ofeach of said clamping leaf springs, and that each of the recessesreceiving said substantially S-shaped end of one of said clamping leafsprings is closed by a ridge having a smaller radius of curvature thanthe radius of curvature of the bend of said S-shaped end remote fromsaid valve body.